Fortunately, I got to live in Townsend for a few years. I have not hiked all 800 miles of trail in the park but have logged over half of it.
The two things I always ask when recommending a hike is "what time of year" and "how far do you want to hike in a day". I hear people say elevation gain is not a problem, but the haul from Gatlinburg to Mt. LaConte past Rainbow falls will tax even the stout at heart.
If you are going to be there in June/July, I would go high and remote. The Rhodo's in bloom on Gregory's Bald is something everyone ought to see once in their life. In April, I would say not to pass up White Oak Sinks. One of, if not the most, picturesque spot in the Park, IMHO. Chimney Tops, Bunion, and even LeConte will be the most crowded along with Andrew's Bald. However, there are several great hikes out of Cataloochee where the great odds are you won't see anyone.
If you want some good views of Cades Cove, you can find them from along Rich Mtn Loop and Indian Grave Gap trails.
History? I would take a boat across Fontana and hike the Hazel Creek area. The shuttle is a little pricey though.
I don't think there are any bad hikes in the Smokies, it's just that some are better than others. Good Luck and have fun.